Windowed door for a heat cleaning oven

ABSTRACT

A door for a forwardly open pyrolytic self-cleaning oven having a hollow space therewithin and including a window comprised of at least two parallel spaced panes. A shutter, having flanges extending from each side into guide slots located within the hollow space and running adjacent each side of the window, is movable from a first position wherein the flanges seat in tapered reductions in the widths of each slot to a second position between the panes obstructing viewing into the oven. The shutter is suspended from flexible cables connected with a crank mounted on the shaft of a rotatable latching handle which the user must move to a latched position, thereby moving the shutter, before a heat cleaning operation can begin.

I United States Patent 1 1 1111 3,881,462

Barnett [45] Ma 6, 1975 WINDOWED DOOR FOR A HEAT Primary ExaminerKenneth W. Sprague CLEANING OVEN Assistant Examiner-Larry I. Schwartz [75] Inventor: Eugene J. Barnett, Mansfield, Ohio Attorney Agent or firm-E" Arenz [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa. [57] ABSTRACT A door for a forwardly open pyrolytic self-cleaning [22] Flled May 1974 oven having a hollow space therewithin and including [21] Appl. No.: 465,985 a window comprised of at least two parallel spaced panes. A shutter, having flanges extending from each 52 us. Cl 126/197; 126/200 hollow Space 51 I t Cl F23 7/00 and runnmg ad acent each s1de of the w1ndow, 1s mov- ITO/173 able from a first position wherein the flanges seat in 0 care tapered reductions in the widths of each slot to a second position between the panes obstructing viewing [56] References cued into the oven. The shutter is suspended from flexible UNITED STATES PATENTS cables connected with a crank mounted on the shaft 3,396,717 8/1968 Winkler et a1. 126/200 of a rotatable latching handle which the user must 3,507,267 4/1970 Lafforgue 126/200 move to a latched position thereby moving the shut- 3,717,138 2/1973 Upp 126/200 ten b f a heat Cleaning Operation can begin. 3,720,196 3/1973 Barnett et al. 126/200 7 Claims, 5 Drawing Figures PATENTEDHAY sms SHEET 3 BF 3 WINDOWED DOOR FOR A HEAT CLEANING OVEN BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to the art of cooking ovens and more particularly to windowed oven doors including shutter arrangements for the windows.

2. Description of the Prior Art The best prior art known to the applicant in this particular field is found in US. Pat. Nos. 3,717,138; 3,565,054; 3,507,267; 3,500,815; and 3.720.196. Some of these arrangements use a one-piece shutter stored in a lower pocket within the door and the shutter is manually elevated by mechanical linkages to a closed or blocking position independent of the operation of the door latching means. Others of these arrangements coordinate the interpositioning of the shutter with the door latching operation but use relatively complex shutter arrangements having multiple part or louvered shutters and interconnecting mechanical linkages. The present invention is a relatively uncomplicated mechanical arrangement using a one-piece shutter which is moved in cooperation with the latching operation.

SUMMARY OF THE INVENTION A door for closing the opening of a cooking oven is provided including at least two spaced wall panels and a window opening in the door comprising at least two parallel spaced panes of glass. The door also includes means for latching the door closed and a shutter for the window. The shutter has flanges extending from each side into guide slots located within the space between the panels and adjacent each side of the window. Suspension means operated by a latching handle move the shutter, when the door is latched closed, from a first position wherein the flange seat in a tapered reductions in the openings of each slot, to a second position between the panes of glass obstructing viewing into the oven. When the door is unlatched the slots guide the gravity return of the shutter to the first position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a cooking range including an oven embodying the invention;

FIG. 2 is a partly broken front elevational view of a range door;

FIG. 3 is a cross sectional view corresponding to one taken along the centerline at the FIG. 1 door in the closed position;

FIG. 4 is a partly broken and sectional isometric view of the shutter subassembly;

FIG. 5 is an elevational view of a guide slot bracket from the shutter subassembly of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 a range is shown having a heat cleaning oven embodying the invention. The range includes a forwardly open oven liner 12 having a heating element 14 therein. The oven is closed by a door 16.

A manually operated latching handle 18 is mounted in the door in an upper central location as shown in FIG. 3. The handle 18 operates a latching mechanism 20 for securing the door when a heat cleaning cycle is to be started. The latching mechanism may also be used to place a lock effecting means in condition to lock the door when the oven temperature has risen above the normal cooking temperature range. An example of an arrangement for accomplishing this is disclosed in US. Pat. No. 3,390,909. As the handle 18 is rotated from the horizontal unlatched position with the door closed, a latching bolt 22 is turned up out of the slot 23 in the top edge of the door. The bolt 22 engages a keeper structure and bell crank assembly 24, FIG. 1, illustrated in block form as mounted in the oven frame structure overlying the top edge of the door when the door is in the closed position. As disclosed in the above referenced patent a linkage connecting the bell crank to a lock means at the rear of the oven places the lock means in a condition for permitting the starting of the heat cleaning cycle.

As shown in FIGS. 2 and 3, the door 16 includes an outer panel 24 and an inner panel 26 and a shutter subassembly 28 secured therebetween. The shutter subassembly 28 is evenly spaced from each side of the door 16 leaving voids between the outer panel 24 and the inner panel 26 on each side of the subassembly 28. These voids are filled with thermal insulation 25 which reduces the rate of heat transfer from the oven to the outer surface of the front panel 24.

As shown in FIGS. 2 through 4, the shutter subassembly 28 includes a pan-shaped main panel 30 having a window opening therein filled by a pane of glass 31. Fixed to each vertical edge of the main panel 30 are guide slot brackets 32 and 34 respectively having slots 36 and 37 cut therein. A shutter 38 spans between the guide slots and includes sidewardly extending flanges 40 and 42 which are received in the guide slots.

The shutter 38 is constructed of sheet metal folded to provide a rectangular cross section as shown in FIGS. 3 and 4. This double walled construction provides an interior air space 44 which also provides an insulating effect. During normal cooking operation the shutter 38 is stored in a lower position shown in FIGS. 2-4 near the bottom of the shutter subassembly 28.

When stored in this lower position rattling of the shutter 38 due to vibrations during opening and closing of the door 16 is reduced by the shutter being self seating in this position. Both guide slots 36 and 37 are shaped as shown in FIG. 5, an elevational view of the guide slot bracket 32 with guide slot 36 cut therein. The guide slot 36 has a forward edge 46 which is straight for almost the length of the slot ending in a rearward taper 48 at the bottom of the slot 36. The rearward edge 50 of the slot 36 is straight from the bottom of the slot to a height slightly less than the height of the shutter 38. At this height the edge 50 is shaped in a rearward upper taper 52 which results in the slot 36 being wider for an upper length 54 and narrower for a lower length 56.

The flanges 40 and 42, which extend from the shutter 38 are formed so that each lower edge is curled at 58 and 60 in FIG. 4. The curls 58 and 60 have sufficient breadth to be seated or wedged in the slot at the lower taper 48 when the shutter is in the lower position. In addition, the top edge 62 and 64 of each flange is also curled to provide sufficient breadth so that the top edges 62 and 64 also seat or wedge in the taper at 52. The top edge and the bottom edge of the shutter simultaneously seat in their respective tapers with top of the shutter being urged forwardly because of the slope of the upper taper at 52 and the bottom of the shutter being urged rearwardly by the slope of the taper at 48 resulting in a firm holding of the shutter at the lower position.

Storage of the shutter 38 in the lower part of the shutter subassembly 28 provides an additional advantage in that there is more room for thermal insulation 66 above the window opening 31 as shown in FIGS. 2-4, to serve as a thermal barrier between the window 31 and the operating mechanism carried by the shutter subassembly 28 thereabove.

The operating mechanism functions as follows: During the heat cleaning operation, the oven door 16 must be latched closed before the oven can be raised to heat cleaning temperatures as explained in US. Pat. No. 3,390,909. As the latching handle 18 is rotated clockwise facing the oven door FIGS. 2-4, the latching bolt 22 is rotated up out of slot 23. As this is done a crank 68 made one piece with the latching bolt 22 and mounted on a rotatable shaft 70 of the latch handle 18, similarly moves in a clockwise direction. The crank 68 is rotatably pinned to a drawing link 72. The drawing link 72 connects with a left draw cable 74 and a right draw cable 76, left and right being established facing the front of the range door 16. The cables 74 and 76 are adjustably connected with the link 72. An adjustment bracket 78 is connected to the link 72 by screws 80 and the cables 74 and 76 are gripped therebetween.

The cables 74 and 76 are connected from the link 72 to the shutter 38 as shown in FIG. 4. The left draw cable 74 is held between the adjustment bracket 78 and the link 72 below the screws 80. The left cable 74 passes from the link 72 and partly wraps around a right corner pin 82 in a counterclockwise direction starting near the bottom of the pin. The left draw cable 74 then passes horizontally across the top of the shutter assembly to partly wrap around a left corner pin 84. It then passes in a downward direction through the guide slot bracket 32 to connect with the top edge 62 of the shutter 38. The right draw cable 76 is gripped between the adjustment bracket 78 and the draw link 72 above the screws 80 and then partly wraps around the right corner pin 82 in a clockwise direction starting near the top of the pin 82 and passes downwardly within the guide slot bracket 34 to be connected with the top edge 64 of the shutter 38.

As indicated by the arrows in FIG. 2 when the handle 18 is rotated from its normal unlatched horizontal position in a counterclockwise direction the crank 68 moves downward drawing the link 72 downward and leftward, in turn drawing the draw cables 74 and 76 in a generally leftward horizontal direction. This movement is transferred by the cables to the shutter 38 drawing the shutter upwardly. The shutter is directed in its upward movement by the flanges 40 and 42 sliding in the guide slots 36 and 37. To avoid possible cocking or jamming problems due to thermal distortion the shutter flanges fit relatively loosely in the wider upper lengths 54 of the guide slots 36 and 37. In addition sideward movement or rotation of the shutter 38 during its vertical movement which could cause cocking is limited by circular studs 86 (FIG. 4) inserted transversely through the flanges 40 and 42 near each corner. The studs 86 slidably bear on the sides of the guide slots 36 and 37 located within the guide slot brackets 32 and 34, maintaining the shutter 38 relatively perpendicular to the guide slot brackets 32 and 34. Additional guiding of the shutter 38 in its vertical movement is achieved by the outer edges of each flange slidably engaging on pins 87 inserted transversely through the brackets 32 and 34 near the upper tapes 52. In the preferred embodiment the studs 86 are coated with a dry, temperature-resistant lubricant which combined with the circular shape of the studs, reduces friction in the movement of the shutter.

In order for the shutter to be drawn to a position which completely obstructs viewing through the window 42, the latching handle 18 must be rotated about one half turn. This moves the crank 68 to point in a leftward direction in a generally horizontal position with the link 72 partly overlapping the crank as shown in phantom in FIG. 2. A recess 88 is made in the profile of the link 72 to allow the link to clear the shaft 70 when in this latched position. The arrangement is retained in this latched position by the inherent friction of the system and a spring stop which is deflected out of the way of travel of the crank 68 as it is rotated but as the crank 68 passes, the stop 90 returns to an interfering position retaining the arrangement in the latched position.

When the self-cleaning operation has been completed the latching handle 18 is rotated from its latched horizontal position in a counterclockwise direction facing the range. This rotation reverses the travel of the crank 68 and the link 72 as described above permitting the force of gravity to return the shutter 38 to its lower seated position shown in FIGS. 2-4.

This arrangement for suspending and moving the shutter as described provides an advantage in that the latching handle 18 must be rotated a significant amount from either horizontal position before appreciable horizontal movement of the cables occurs. This results from the generally aligned relation of the lever or crank 68, link 72, and the common location of the cables at 82 whenever the crank is in a generally horizontal position. This alleviates the need for providing the arrangement with a lost motion device or other mechanical means to prevent attempts by the user to open the door while the oven is in a heat cleaning operation. from causing movement of the shutter 38.

In addition since the shutter 38 seats and is firmly held in the lower storage position precise adjustment of the cables 74 and 76 is not required to properly locate the shutter in the storage position. Linear travel of the cables is small during the last few degrees of angular displacement of the handle 18 to either opposite position so that slight variations in the synchronization of the pull provided by the cables does not affect positioning of the shutter nor would these variations affect travel of the shutter 38 because the studs 86 assure proper alignment of the shutter with respect to the guide slots.

I claim:

1. A cooking oven comprising:

means defining a forwardly open oven;

:1 door for closing said oven including at least a first panel and a second panel spaced apart from said first panel;

a window in said door including at least a pair of spaced apart panes on opposite sides of a generally planar space defined in part between said windows;

a shutter having sidewardly extending flanges positionable in said door to seat in a first position between said first panel and said second panel and movable to at least a second position in said generally planar space between said panes to obstruct viewing therethrough into said oven;

means defining guide slots disposed transverse to said panels and said panes and further defining said planar space between said panes; said slots receiving said flanges therein; said slots including means to receive said flanges in a seated relationship at said first position;

means for latching said door closed;

means for positioning said shutter within said door. said positioning means connected with said latching means to locate said shutter in said first position with said door in an unlatched condition and to draw said shutter from said first position to said second position when said door is latched closed; and

said means to receive said flanges in a seated relationship comprise lower tapers at the bottom of each of said slots, and upper tapers at a position in each slot corresponding to the top of each flange when said shutter is seated. said upper and lower tapers having oppositely directed slopes to import a tilted disposition to said shutter in its seated position,

2. The oven of claim 1 wherein:

said guide slots are narrower for a length adjacent the first position of said shutter and wider for a length adjacent said second position of said shutter.

3. The oven of claim 1 wherein:

said sidewardly extending flanges include stud means extending transverse to each corner thereof. said stud means being positioned to restrict sideward movement and coating of said shutter by slidably bearing on the distal edges of said guide slots.

4. A windowed door construction for a self-cleaning oven, comprising:

a door having a viewing window;

a single shutter in said door movable from a lower unobstructing position to an upper, windowobstructing position;

track means at the sides of said shutter for guiding said shutter in its movement a rotatable door latching mechanism;

a lever rotatable with said latching mechanism through about a half circle for effecting movement of said shutter, said lever extending generally horizontally at its opposite rotated positions;

a cable extending from each of the opposite ends of said shutter to a common location generally aligned horizontally with the axis of said level in its opposite rotative positions; and

link means connecting said cable means at said common location to said lever;

whereby the generally aligned relationship of said lever, link means and common location at the opposite rotative positions of said lever results in limited linear displacement of said cables and said shutter relative to the angular displacement of said lever in the end travel portions of said lever.

5. A construction according to claim 4 wherein:

said shutter includes upper and lower endwise projecting portions received in said track means. said upper projecting portions having a greater front to rear dimension than said lower projecting portions; and

said track means include an upper slot of a width to accommodate movement therealong of said upper projecting portion and a lower slot of narrower width sufficient to accommodate movement of only said lower projecting portion.

6. A construction according to claim 5 wherein:

the lower ends of said upper and lower slots are tapered to form seats to receive said upper and lower projecting portions, respectively, in seated relationship in said lower position of said shutter.

7. A construction according to claim 5 wherein:

said shutter is comprised of spaced-apart panels forming a hollow interior; and

said upper and lower endwise projecting flanges are formed from the upper and lower edge portions of endwise projecting flanges of one of said panels. 

1. A cooking oven comprising: means defining a forwardly open oven; a door for closing said oven including at least a first panel and a second panel spaced apart from said first panel; a window in said door including at least a pair of spaced apart panes on opposite sides of a generally planar space defined in part between said windows; a shutter having sidewardly extending flanges positionable in said door to seat in a first position between said first panel and said second panel and movable to at least a second position in said generally planar space between said panes to obstruct viewing therethrough into said oven; means defining guide slots disposed transverse to said panels and said panes and further defining said planar space between said panes, said slots receiving said flanges therein, said slots including means to receive said flanges in a seated relationship at said first position; means for latching said door closed; means for positioning said shutter within said door, said positioning means connected with said latching means to locate said shutter in said first position with said door in an unlatched condition and to draw said shutter from said first position to said second position when said door is latched closed; and said means to receive said flanges in a seated relationship comprise lower tapers at the bottom of each of said slots, and upper tapers at a position in each slot corresponding to the top of each flange when said shutter is seated, said upper and lower tapers having oppositely directed slopes to import a tilted disposition to said shutter in its seated position.
 2. The oven of claim 1 wherein: said guide slots are narrower for a length adjacent the first position of said shutter and wider for a length adjacent said second position of said shutter.
 3. The oven of claim 1 whErein: said sidewardly extending flanges include stud means extending transverse to each corner thereof, said stud means being positioned to restrict sideward movement and coating of said shutter by slidably bearing on the distal edges of said guide slots.
 4. A windowed door construction for a self-cleaning oven, comprising: a door having a viewing window; a single shutter in said door movable from a lower unobstructing position to an upper, window-obstructing position; track means at the sides of said shutter for guiding said shutter in its movement a rotatable door latching mechanism; a lever rotatable with said latching mechanism through about a half circle for effecting movement of said shutter, said lever extending generally horizontally at its opposite rotated positions; a cable extending from each of the opposite ends of said shutter to a common location generally aligned horizontally with the axis of said level in its opposite rotative positions; and link means connecting said cable means at said common location to said lever; whereby the generally aligned relationship of said lever, link means and common location at the opposite rotative positions of said lever results in limited linear displacement of said cables and said shutter relative to the angular displacement of said lever in the end travel portions of said lever.
 5. A construction according to claim 4 wherein: said shutter includes upper and lower endwise projecting portions received in said track means, said upper projecting portions having a greater front to rear dimension than said lower projecting portions; and said track means include an upper slot of a width to accommodate movement therealong of said upper projecting portion and a lower slot of narrower width sufficient to accommodate movement of only said lower projecting portion.
 6. A construction according to claim 5 wherein: the lower ends of said upper and lower slots are tapered to form seats to receive said upper and lower projecting portions, respectively, in seated relationship in said lower position of said shutter.
 7. A construction according to claim 5 wherein: said shutter is comprised of spaced-apart panels forming a hollow interior; and said upper and lower endwise projecting flanges are formed from the upper and lower edge portions of endwise projecting flanges of one of said panels. 